Study Of Medium And Small Power Ultrasonic Power Supply Based On DSP For Al Casting-Rolling

Aluminum materials have been widely used in industrial production and life area, and grain size of aluminum strip is directly related to its quality. The ultrasonic leading in aluminum cast-rolling process can improve the quality because ultrasonic cavitations and acoustic streaming effect can refine its grain size. The ultrasonic power is the key parts of the ultrasonic machining technology because its performance affects the machining effect. So this paper mainly focuses on several key problems in ultrasonic power systems, which are power controlling, frequency tracking, transducer matching and load matching, and figures out main components parameters.Through analyzing the ultrasonic power structure and considering the maximum output of ultrasonic power, the main circuit structure of ultrasonic power is composed of uncontrolled rectifier to get direct current, buck chopper to realize power control and half bridge inverter to get high frequency alternating current.When ultrasonic transducer works at series resonance, it shows capacitive reactance, so it must be matched with inductor and capacitor. Because the dynamic matching is better than static matching, through detecting the transducer's static capacitance, it can adjust digital inductance to get high-efficiency performance. In order to realize load matching, a high frequency transformer is designed to add between the load and power. During ultrasonic transducer working, its resonant frequency may change for temperature change, so the phase-locked loop based on DSP can realize tracking its frequency changes. Due to the model of Buck chopper is complicated and strong nonlinear, the fuzzy control way can get good control effect.The simulation results show that:through the fuzzy-control way, it is able to achieve fast and stable power regulation, and digital phase-locked loop ensures that the load works at its resonant. The research of the paper has an important significance of study on the ultrasonic power supply.